"The U.S. Postal Service has overfunded its federal pension obligations by ... $13.5 billion, [as of the end of] the federal fiscal year ending Sept. 30, 2011, according to a report issued Monday by the agency's inspector general [that shows a $269 million present value liability and $282 million in assets]. The inspector general suggested reverting the surplus money to the Postal Service. But the Office of Personnel Management is not permitted to return surplus contributions to federal agencies. That would require an act of Congress."